Traffic Flows Before Load Balancing
Purpose
The following sample output illustrates the details to look for when you issue different show commands to check if traffic is balanced. The following output is before load balancing is configured and is taken from transit router R2 in the network shown in Load-Balancing Network Topology.
Action
To check the distribution of traffic across interfaces and LSPs, use the following CLI operational mode commands:
Sample Output 1
user@R2> show route | find mpls
mpls.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
0 *[MPLS/0] 1d 00:12:08, metric 1
Receive
1 *[MPLS/0] 1d 00:12:08, metric 1
Receive
2 *[MPLS/0] 1d 00:12:08, metric 1
Receive
100112 *[RSVP/7] 13:10:36, metric 1
> via so-0/0/1.0, label-switched-path lsp1
100128 *[RSVP/7] 13:01:08, metric 1
> via so-0/0/1.0, label-switched-path lsp4
100144 *[RSVP/7] 00:26:49, metric 1
> to 10.0.12.13 via fe-0/1/0.0, label-switched-path r0-r6
100160 *[RSVP/7] 00:23:25, metric 1
> via so-0/0/2.0, label-switched-path lsp2
100176 *[RSVP/7] 00:23:25, metric 1
> via so-0/0/2.0, label-switched-path lsp3
Sample Output 2
user@R2> monitor interface traffic R2 Seconds: 89 Time: 14:33:09 Interface Link Input packets (pps) Output packets (pps) so-0/0/0 Up 0 (0) 0 (0) so-0/0/1 Up 90 (1) 91 (1) so-0/0/2 Up 118 (1) 100122 (0) so-0/0/3 Up 0 (0) 0 (0) fe-0/1/0 Up 100119 (0) 115 (0) fe-0/1/1 Up 0 (0) 0 (0) fe-0/1/2 Up 0 (0) 0 (0) fe-0/1/3 Up 0 (0) 0 (0) [...Output truncated...]
Sample Output 3
user@R2> show mpls lsp statistics Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 5 sessions To From State Packets Bytes LSPname 192.168.0.1 192.168.6.1 Up 0 0 lsp2 192.168.0.1 192.168.6.1 Up 112026 22853304 lsp1 192.168.0.1 192.168.6.1 Up 0 0 lsp3 192.168.0.1 192.168.6.1 Up 0 0 lsp4 192.168.6.1 192.168.0.1 Up 0 0 r0-r6 Total 5 displayed, Up 5, Down 0
Meaning
Sample Outputs 1 through 3 from transit router R2 show that traffic is not balanced across LSPs or interfaces.
Sample Output 1 for the show route command shows that all LSPs have the same metric (1) to the destination, even though they are traversing different interfaces. lsp1 and lsp4 are using so-0/0/1, while lsp2 and lsp3 are using so-0/0/2.
Sample Output 2 for the monitor interface traffic command shows that traffic is not evenly balanced across interfaces so-0/0/1 and so-0/0/2. Almost all traffic is going out so-0/0/2.
Sample Output 3 for the show mpls lsp statistics command shows that traffic across LSPs is not balanced. All traffic is going over lsp1.
Related Topics
For additional information about MPLS fast reroute and MPLS protection methods, see the following:
- Junos Feature Guide
- Junos MPLS Applications Configuration Guide
- Semeria, Chuck. RSVP Signaling Extensions for MPLS Traffic Engineering. White paper. 2002
- Semeria, Chuck. IP Dependability: Network Link and Node Protection. White paper. 2002
- RFC 4090, Fast Reroute Extensions to RSVP-TE for LSP Tunnels
The Junos OS uses the load-balancing function across different protocols and features. For information about other types of load balancing, see the following:
- Option: Optimizing VPLS Traffic Flows, Junos Feature Guide
- Protocol-Independent Load Balancing for Layer 3 VPNs, Junos VPNs Configuration Guide
- Load Balancing Among Multiple Monitoring Interfaces, Junos Services Interfaces Configuration Guide
